Project description:Tumor cells were observed to undergo extravasation through intrivital imaging and immediately following the extravasation they were isolated and compared to control cells using RNA-seq.
Project description:Canine osteosarcoma cells were observed to undergo extravasation through intrivital imaging. Then the extravasated cells were isolated and established as sublines and compared to control cells using RNA-seq.
Project description:Metastases, which largely rely on hematogenous dissemination of tumor cells via the vascular system, significantly limit prognosis of patients with solid tumors. To colonize distant sites, circulating tumor cells must destabilize the endothelial barrier and transmigrate across the vessel wall. Here we performed a high-content screen to identify drugs that block tumor cell extravasation by testing 3520 compounds on a transendothelial invasion co-culture assay. Hits were further characterized and validated using a series of in vitro assays, a zebrafish model enabling 3-D visualization of tumor cell extravasation, and mouse models of lung metastasis. The initial screen advanced 38 compounds as potential hits, of which 4 compounds enhanced endothelial barrier stability while concurrently suppressing tumor cell motility. Two compounds: niclosamide and forskolin, significantly reduced tumor cell extravasation in zebrafish and niclosamide drastically impaired metastasis in mice. Because niclosamide had not previously been linked with effects on barrier function, we performed single cell RNA sequencing to reveal mechanistic effects of the drug on both tumor and endothelial cells. Importantly, niclosamide affected homotypic and heterotypic signaling critical to intercellular junctions, cell-matrix interactions, and cytoskeletal regulation. Proteomic analysis indicated that niclosamide-treated mice also showed reduced levels of kininogen, the precursor to the permeability mediator bradykinin. Our findings designate niclosamide as an effective drug that restricts tumor cell extravasation through modulation of signaling pathways, chemokines, and tumor-endothelial cell interactions.
Project description:Metastasis accounts for the majority of all cancer deaths, yet the process remains poorly understood. A pivotal step in the metastasis process is the exiting of tumor cells from the circulation, a process known as extravasation. However, it is unclear how tumor cells extravasate, and if multicellular clusters of tumor cells posses the ability to exit as a whole or must first disassociate. In this study, we use in vivo zebrafish and mouse models to elucidate the mechanism tumor cells use to extravasate. We found that circulating tumor cells exit the circulation using the recently identified extravasation mechanism, angiopellosis, and do as both clusters and individual cells. We further show that when melanoma and cervical cancer cells utilize this extravasation method to exit as clusters, they exhibit an increased ability to form tumor at distant sites through the expression of unique genetic profiles. Collectively, we present a new model for tumor cell extravasation of both individual and multicellular circulating tumor cells.